Given a buf, starting at offset (default: 0), begin decoding bytes as VarInt encoded bytes, for a maximum of 5 bytes (offset + 5). The returned tuple is of the decoded varint 32-bit number, and the new offset with which to continue decoding other data.

VarInts are not 32-bit by default so this should only be used in cases where the varint is assured to be 32-bits. If in doubt, use decode().

To know how many bytes the VarInt took to encode, simply negate offset from the returned new offset.